WhoTracks.me observed a shift in traffic from Google’s European search results pages towards google.com in April. It seems to be Google's attempt to keep their tracking cookies.

There have been recent reports that Google has started redirecting users from regional variants of Google search (served on google.{de, fr, co.uk, etc}) to google.com for search results. This has implications for the 4th most prevalent tracker on the web, so we decided to check the data to see what is going on.

By looking at WhoTracks.me data from April, we see that around April 16th there is a shift in traffic from Google’s European search results pages (www.google.{de,fr,at,co.uk,etc}) towards www.google.com. The figure below shows that the former domains all saw a 50% drop in number of page loads in the week after April 16th, while www.google.com is up 100-150%, suggesting Google are doing a gradual rollout of this change. These changes lie well outside the bounds of the weekly traffic fluctuations we usually see.

Percentage change in traffic to Google search result pages, April 2018

We can further see the magnitude of this change by focusing on data for Germany. If we look at the relative proportion of pages loaded on www.google.de and www.google.com in Germany over the last month, we see a marked increase, with the share of traffic to www.google.com going up from around 5% to over 40%.

Search results pages used in Germany, April 2018

Why is Google doing this? We don’t know – we’re not aware of any official announcement. However, one reason for this could be a reaction to increased usage of restrictive cookie settings, such as allowing cookies only from visited sites, or Apple’s Intelligent Tracking Prevention. If a user is rarely visiting the google.com domain, these technologies can expire this cookie earlier, or prevent its use in third-party contexts. As google.com is the domain used to authenticate with Google services, if the browser sends google.com cookies in third-party context, these visits can be directly attributed to one’s Google profile. Therefore, this change increases the likelihood that the user will have recently visited www.google.com, and therefore Google’s tracking can continue uninterrupted.

Tracking from google.* domains reaches 30% of web traffic, and the majority of this reach is contributed by the google.com domain. As, with this change, it is very difficult to avoid visiting google.com domain as a first party, preventing this tracking in a vanilla browser would require disabling all third-party cookies. Alternatively, Cliqz’s and Ghostery’s AI-powered anti-tracking technologies block all third-party tracking cookies.